Delivery fly assemblies are used to move objects, generally comprising sheet-like material, from a first location to a second location. Often, a delivery fly assembly is associated with printing apparatus and is used to move printed material from a first location adjacent a folding cylinder to a second location on a conveyor.
A delivery fly assembly typically has a plurality of flywings defining fly pockets therebetween, each fly pocket being used to deliver a printed product from the first location to the second location. Delivery is accomplished by rotation of the fly assembly, each fly pocket receiving printed material from the first location and rotating with the fly assembly to the second location where the printed material is dropped off. Sometimes it is desired to change the number of fly pockets on the fly assembly, an increasing number generally resulting in decreased space between printed products deposited on the conveyor. Six, seven or eight fly pockets, for example, are common in the printing industry.
The printed material must somehow be removed from the fly pockets during rotation of the fly assembly in order to be deposited at the second location. A conventional way to remove printed material from the pockets is to have a stationary stop such as a shoe located in the path of the rotating printed material. When the printed material contacts the stop, the printed material can no longer rotate with the fly pocket and is ejected from the pocket while the pocket continues to rotate. A disadvantage of the stationary stop is that removal is abrupt rather than gradual and, consequently, the stop may dent or otherwise deform the printed material.
Another conventional way to remove printed material from the pockets comprises a rotating wheel with teeth. The wheel is rotated slightly slower than the rotation of the fly assembly. The rotational axis of the wheel is typically parallel to the axis of the fly assembly but is offset so that those two axes are not coaxial. As the fly assembly rotates, printed material contacts a tooth of the rotating wheel and is ejected from the fly pocket because the wheel rotates more slowly than the fly assembly. A disadvantage of this stripping mechanism is that it requires a separate drive for the rotating wheel. Also, the relatively complicated timing required for proper operation is very difficult to adjust in the event that an operator desires to change the rate of delivery or to change the relative positions of the first and second locations or to change the number of pockets. In some instances, gears would have to be replaced or a different wheel would be necessary to achieve proper timing.
In another conventional design, the stripper comprises a belt that is driven at a speed that is slightly slower than the rotation of the fly assembly. The belt has teeth that engage and eject the printed material. As with the rotating wheel, an additional drive is necessary and any changes in the operating speed or the number of fly pockets may require significant readjustments in the system including, possibly, switching to a belt on which the spacing of the teeth is different.